The body control module (BCM) controls the DEFOG relay circuit. When the ignition switch is in RUN position and the operator has depressed the defogger switch, the BCM provides power to the DEFOG relay control circuit.
This diagnostic procedure supports the following DTC:
DTC B0283 Electric Rear Defrost
The system voltage must be between 9-16 volts.
The BCM detects a short to battery positive voltage in the DEFOG relay control circuit when the BCM is trying to energize the relay.
The BCM detects that the DEFOG relay control circuit is open.
The condition above must be present for more than 1 second.
The BCM stores DTC B0283 in memory. The DEFOG will not operate.
• | A current DTC clears when the malfunction is no longer present. |
• | A history DTC clears when the module ignition cycle counter reaches the reset threshold, without repeat of the malfunction. |
The number(s) below refer to the step number(s) on the diagnostic table.
Tests for battery positive voltage at the coil side of the rear window defogger relay. The EF25 (10A) fuse supplies power to the coil side of the DEFOG relay.
Tests the control circuit side of the DEFOG relay for faults that cause DTC B0283.
Listen for an audible click when the DEFOG relay operates. Command both the ON and OFF states.
Verifies that the BCM is providing ground to the DEFOG relay.
Step | Action | Value(s) | Yes | No |
---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |
Does the test lamp illuminate? | -- | Go to Step 3 | Go to Step 8 | |
Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 4 | |
Does the test lamp turn ON and OFF? | -- | Go to Step 6 | Go to Step 5 | |
Test the control circuit of the DEFOG relay for an open. Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 7 | |
6 | Inspect for poor connections and terminal damage at the relay socket. Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 9 |
7 | Inspect for poor connections at the harness connector of the body control module (BCM). Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 10 |
8 | Repair the short to ground, poor connection or an open in the EF25 (10A) fused voltage supply circuit. Did you complete the repair? | -- | Go to Step 11 | -- |
9 | Replace the DEFOG relay. Did you complete the replacement? | -- | Go to Step 11 | -- |
10 | Replace the BCM. Refer to Body Control Module Replacement . Did you complete the replacement? | -- | Go to Step 11 | -- |
11 |
Does the DTC reset? | -- | Go to Step 2 | System OK |